1. Home
  2. /
  3. Blog
  4. /
  5. My Radiator Is Leaking – 3 Reasons Why!
My Radiator Is Leaking – 3 Reasons Why!

My Radiator Is Leaking – 3 Reasons Why!

‘Why is my radiator leaking?’ If you’re asking this question, you need answers – and quickly. Addressing a radiator leak efficiently could help to prevent secondary damage to your property, while giving you clarity on other home heating issues too.

In this blog, we highlight the common causes of a leaky radiator, tips on avoiding one, and advice on how to deal with water leak damage.

What are the causes of a leaking radiator?

As there are many different types of leaks that can occur, it’s important to know the common causes. This will help you identify what’s causing your radiator leak, allowing you to take appropriate action. The source of escaping water can range from the body of the radiator to the body of the valve, or even the feeder pipe. Let’s take a closer look…


This can be caused by either a build-up of debris or by air getting inside the system, potentially leading to rust and a pinhole leak. This is a small hole that can occur in the body of the radiator, which may get bigger over time.

Loose or damaged valve or gland

The valve is the plastic-capped knob located on the side of the radiator, and the gland sits beneath this. Damage can occur through degradation or impact. Alternatively, they may not have been tightened properly. Both situations can potentially lead to a leaky radiator valve.

Loose or damaged spindle

This is the joint connecting the valve to the main radiator. Just like the valve, leaks can occur through wear and tear, or the joint not being tight enough.

How to avoid a radiator leak

The methods used for avoiding or fixing the problem will vary depending on the type of leak and the cause behind it. Sometimes, however, the issue may require the expert help of a plumber or specialist water leak and damage restoration company. If in doubt, always call a professional.


Dealing with rust isn’t the same as tightening or replacing a part. You may need to replace the radiator entirely to avoid further leaks.

Loose or damaged valve or gland

Ensure that your valve isn’t loose and tighten the gland nut. If water still escapes, you may need to replace or fix the leaking radiator valve. Ensure you drain the central heating system before either fitting the new part(s) or fixing the existing valve or gland with PTFE tape. Make sure you bleed the radiator afterwards to release excess air.

Loose or damaged spindle

Check that the spindle is tight enough. If this doesn’t stop the leak, you can attempt to repair it. Again, drain all water from the system. Undo the gland nut and wrap spindle packing or PTFE tape down into the spindle, and tighten the nut back up. Alternatively, you may need to replace the part.

What damage can be caused by a leaking radiator?

Pooling water is common with leaking radiators. It’s no surprise that this can cause real damage to your property, including:

  • Electrical hazards or damage
  • Flooring or furniture damage
  • Staining, mould growth and foul smells throughout your home

How Rainbow International can help

After fixing a leak, you may experience staining, black mould and bad odours from the water damage. This can create uncomfortable and unhygienic living conditions.

With over 25 years of experience, Rainbow International can minimise secondary damage like this and return your property to its pre-incident condition quickly and efficiently. Visit our water damage restoration page to learn more.

Frequently asked questions

Is a leaking radiator dangerous at home?

Yes. Among other things, pooling water can lead to electrical hazards. It can also cause black mould, potentially leading to respiratory issues.

Does a leaking radiator affect the boiler?

Yes. It can lead to low boiler pressure, which will affect the radiator’s output and overall heating efficiency.

Do radiators leak when they need bleeding?

No. However, leaks can occur from the same place where you bleed your radiator.

What happens if you don’t fix a leaking radiator?

You may encounter water damage, as well as poor heating efficiency – which can cause your energy bills to rise.

Published: 23 Dec 2021